Assembly Precautions
Piston
(1) Piston Clearance.
Measure the maximum
diameter of the piston, and check whether piston-to-bore clearance is normal.
Pistons
are available from grades 1 through 4. If the clearance is less
than specified, correction by honing is needed.

(6)
Check clearance at the valve recess on the top of piston. Place clay on the
valve recess before installing the cylinder head, and correctly adjust the valve
timing, then turn the crankshaft one complete turn. Check depresssion of the
clay, to determine clearance. If abnormal resistance is felt when turning the
crankshaft, it is an indication of interference between piston and valve; cease
rotation of crankshaft, and correct the valve recess.